Medium effects in ( pi, pi ' gamma ) angular correlations on 12C(2(+)).

Pion-..gamma.. angular correlations have been measured both in and out of the reaction plane for the reaction /sup 12/C(..pi..,..pi..')/sup 12/C/sup */(2/sup +/, 4.44 MeV), /sup 12/C/sup */..-->../sup 12/C(g.s.)+..gamma... Data are presented at a pion momentum transfer of q = 0.47 fm/sup -1/ for incident pion energies of 116, 140, 162, 180, and 226 MeV and at q = 0.85 fm/sup -1/ for energies of 116, 162, and 226 MeV. A detailed description of the experimental setup together with the applied test procedures and of the data analysis is given. The data are compared to predictions of the ..delta..-hole model and its static limit.